Effects of recombinant gamma interferon and tumor necrosis factor on in vitro interactions of human mononuclear phagocytes with Coccidioides immitis.

Human peripheral blood monocytes readily phagocytized Coccidioides immitis endospores (2 to 5 microns) in vitro. Within 24 to 30 h at 37 degrees C, the phagocytized endospores started developing into immature spherules. However, when the monocytes were incubated with recombinant human gamma interferon (rIFN-gamma) or recombinant human tumor necrosis factor alpha (rTNF-alpha) and then infected, fewer endospores developed into spherules. Treatment with rIFN-gamma or rTNF-alpha activated the fungicidal capabilities of the monocytes as evidenced by the significant reduction in CFU that could be recovered from rIFN-gamma- or rTNF-alpha-activated monocytes compared with nontreated controls.